Myocardial tissue characterization in Chagas' heart disease by cardiovascular magnetic resonance

Abstract

BackgroundChagas’ heart disease is an important public health problem in South America. Several aspects of the pathogenesis are not fully understood, especially in its subclinical phases. On pathology Chagas’ heart disease is characterized by chronic myocardial inflammation and extensive myocardial fibrosis. The latter has also been demonstrated by late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR). In three clinical phases of this disease, we sought to investigate the presence of LGE, myocardial increase in signal intensity in T2-weighted images (T2W) and in T1-weighted myocardial early gadolinium enhancement (MEGE), previously described CMR surrogates for myocardial fibrosis, myocardial edema and hyperemia, respectively.MethodsFifty-four patients were analyzed. Sixteen patients with the indeterminate phase (IND), seventeen patients with the cardiac phase with no left ventricular systolic dysfunction (CPND), and twenty-one patients with the cardiac phase with left ventricular systolic dysfunction (CPD). All patients underwent 1.5 T CMR scan including LGE, T2W and MEGE image sequences to evaluate myocardial abnormalities.ResultsLate gadolinium enhancement was present in 72.2 % of all patients, in 12.5 % of IND, 94.1 % of the CPND and 100 % of the CPD patients (p < 0.0001). Myocardial increase in signal intensity in T2-weighted images (T2W) was present in 77.8 % of all patients, in 31.3 % of the IND, 94.1 % of the CPND and 100 % of the CPD patients (p < 0.0001). T1-weighted myocardial early gadolinium enhancement (MEGE) was present in 73.8 % of all patients, in 25.0 % of the IND, 92.3 % of the CPND and 94.1 % of the CPD (p < 0.0001). A good correlation between LGE and T2W was observed (r = 0.72, and p < 0.001).ConclusionsIncrease in T2-weighted (T2W) myocardial signal intensity and T1-weighted myocardial early gadolinium enhancement (MEGE) can be detected by CMR in patients throughout all phases of Chagas’ heart disease, including its subclinical presentation (IND). Moreover, those findings were parallel to myocardial fibrosis (LGE) in extent and location and also correlated with the degree of Chagas’ heart disease clinical severity. These findings contribute to further the knowledge on pathophysiology of Chagas’ heart disease, and might have therapeutic and prognostic usefulness in the future.

Cardiac Magnetic Resonance-Verified Myocardial Fibrosis in Chagas Disease: Clinical Correlates and Risk Stratification

“…This finding may strengthen the hypothesis that MF in CD is related to arrhythmias and sudden death, which has also been suggested by previous work relating MF and electrophysiological study. 18 On the other hand, patients with lack of clinical cardiomyopathy (IND group) had significantly less extensive MF (0.63±1.4%), confirming two previous MRI studies 15,16 and one pathological study 21 that had shown only minor and focal inflammation and fibrosis in the so-called indeterminate CD presentation. The percentage of MF based on MDE-CMR was progressively and strongly associated with the clinical severity or Rassi score (r = 0.76).…”

“…10 Chagas disease is pathologically characterized by post-inflammatory myocardial fibrosis (MF), 11-13 which can be reliably identified by cardiac magnetic resonance (CMR) imaging using the myocardial-delayed enhancement technique (MDE). 14-16 Since CMR-verified MF has been demonstrated to be an important predictor of arrhythmias and sudden death in several non ischemic cardiomyopathies, such as hypertrophic cardiomyopathy, 17 and also in a pilot study of CD, 18 we propose that a quantitative extent of MF should also offer prognostic value. The relationship between MF and the Rassi score, 10 a validated prognostic score, in patients with and without apparent cardiomyopathy was evaluated in this study, what, by our knowledge, has not yet been performed systematically.…”

Chagas' heart disease: gender differences in myocardial damage assessed by cardiovascular magnetic resonance

“…In mouse models, this immune response against T. cruzi infection was more unfavorable in male species, and linked to gonadal hormone differences [24, 25]. MF measured by CMR is a key marker of myocardial damage in non-ischemic cardiomyopathies [26–28] and, likewise, in Chagas’ heart disease [6, 8]. For our patients, we found that the association between gender and LVEF was mediated by the amount of MF (53% of the effect was mediated).…”

“…From 2 previous studies [6, 8], 62 adults with chronic Chagas’ disease followed at Heart Institute (InCor), referred to CMR, from 2004 to 2012 and with low probability of having severe coronary artery disease (CAD) [9] were included in the study. We used a validated high-risk CAD score [9] based on the following clinical characteristics recorded at the time of CMR: age (−1 to 10 points), male sex (3 points), diabetes (2 points), hypertension (1 point), current smoking (2 points), hypercholesterolemia (1 point), family history of CAD (2 points), history of peripheral vascular disease (2 points), and chest pain symptoms (0–2 points).…”

Review of Journal of Cardiovascular Magnetic Resonance 2015

“…Fifty-four patients were analyzed. Increase in T2-weighted (T2W) myocardial signal intensity and T1-weighted myocardial early gadolinium enhancement (MEGE) could be detected by CMR in patients throughout all phases of Chagas’ heart disease, including its subclinical presentation (IND) [89]. Moreover, findings were parallel to myocardial fibrosis (LGE) in extent and location and also correlated with the degree of Chagas’ heart disease clinical severity.…”